flashes near the blind spot

[Staphy]

Dear John,

I am a female (biochemist), in my late thirties and highly myopic (-13) and I have a few questions regarding recent vision changes in my left eye. See also my previous posts, for which I gratefully thank you for your very helpful answers. Below I start with a concise and complete history with what may be of diagnostic relevance.

History:
mid16: woke up with a sore left eye as I had been lying on it; on another occasion I got some peroxide in my left eye when dying my hair and I flushed it with excess water; sep16 I cought a viral infection more persistent than common flu; during the year I noticed now and then a slight blurred vision with my left eye
okt16: @ophtamologist: developed astigmatism (-1@90deg)  in left eye in short time period with pain in left eye, myopia of -13 for both eyes and 17 mm Hg in right eye (visual aquity 160%) and 19 mm Hg in left eye (visual aquity 90%), no staphyloma
jan17: @ophtamologist: same complaint, pain and poor vision left eye, no diagnosis nor solution, so
feb17: @neurologist: persistent pain in left eye with migraine behind left eye, MRI performed, diagnosis optical neuritis suspect -> treatment with 112 mg total dosis dexamethason during 28 days (ie daily 4 mg)
mar17: @ophtamologist: sudden retinal hemorrhage left eye (just right after dexacourse), no treatment (because most likely corticosteroid induced bleeding, no NV established by FAG), instead multiple follow-ups monitoring recovery
apr17: @ophtamologist: during follow-up I reported faint arc shaped flashes (most apparent in dark) right on the edge of blind the spot in the left eye, neurological problem? the flashes may have been there for longer time, I can't tell for sure
may17: @ophtamologist: final follow-up, OCT clear, no traces of hemorrhage, I still have a very slight deformation on Amsler grid left from point of focus with a sharp nick in a vertical line, also the whole spot where hemorrhage was is still slightly discolored
sep17: @neurologist: flashes most likely retinal problem? still no explanation
aug17: @opthamologist: visual field test showed borderline glaucoma for left eye, test went well for right eye
oct17: @optician: new prescription glasses OD -13 (unchanged, stable for at least 4.5 years) and OS -13 + -1.5@90deg (astigmatism increased even further, corneas are both perfectly spherical), visual aquity 150% for both eyes, warned me for high eye pressure of about 22 mm Hg in both eyes
nov17: @ophtamologist: pain in left eye more persistent and experience more frequent/brighter arc shaped flashes near the edge of the blind spot, I feel that the blind spot is enlarged and more close to the central vision (moreover Amsler gridlines are strongly curved near the blind spot of the left eye), also overal image of left eye (especially second quadrant, upper left of central vision) seems more dim with less contrast sensitivity, no retinal detachment observed, both eyes look fine, however oculair pressure increased in both eyes to 21 mm Hg, it does run in my family so perhaps it is glaucoma? -> treatment initiated with timolol gel drops 1 mg/g one drop per eye per day

Questions:
- My astigmatism (only my left eye) is for sure not corneal, must it then be lenticular? Or can it also be explained for example by the deformation of the back of my eye (ie start of staphyloma)? When my pupils are dilated, the astigmatism in my left eye gets way worse, while my right eye keeps its sharp vision (this once used to be the case for my left eye as well). Also does the exact 90deg, "against the rule", perhaps give a clue?
- My eye pressure in both eyes increased over the last year, is it likely that the elevated pressure causes the onset of astigmatism (either lenticular (slightly subluxed or tilted or cataract or...) or by deforming the back of the eye or ...)? Note that I never had any astigmatism before, so it is a completely new phenomenon to me.
- What may be the cause of arc shaped flashes near the optic disc in (only) my left eye? I am absolute certain of their location (and it is always the same spot, so PVD does not seem likely as it should stop at one point right?) and it is not near where the hemorrhage was. So far no one could give me an answer. Can it be that the increased eye pressure is stimulating the optic nerve? Or perhaps it is a remnant of (the never confirmed) optical neuritis? I don't see these flashes though when I am completely at rest during the night.
- Is timolol effective in lowering my eye pressure? I checked the pressure today at my optician, but so far no effect was shown. Also I still have eye pain and frequent flashes. Perhaps it takes more time for the timolol treatment to take effect?

Medication:
Among other medication I take occassionally propranolol (10 mg tablets). I noted that this seems to reduce the pain in my eye and the occurence of the flashes for a couple of hours. Perhaps propranolol also positively affects the intraocular pressure as it is a beta blocker as is timolol. Though, with the timolol drops I don't have this effect yet. So for now I rely on propranolol.

Goal:
Ideally I want to reverse the newly developed astigmatism in my left eye. Is that possible? But I am happy if I can at least do something to reduce the pain and flashes, that actually worries me the most, and maintain a stable and healthy vision. What would be your diagnosis based on the above? Or what else needs to be done to get a proper diagnosis and treatment?

I really hope to hear from you.

Best regards,
Staphy

[JohnHaganMD]

You have a complex problem and there are more than one factor's going on. Let me address them in turn.

1. Have you had a corneal topography done? If not you cannot say that you have no corneal astigmatism. There is no reason for you to develop lenticular astigmatism. It's relatively rare and doesn't develop quickly. Must have corneal toporgraphy done both eyes.
2. intraocular pressure (IOP) will not cause flashes in the eye or cause astigmatism. Your IOP isn't that high. You may not have glaucoma.   Glaucoma is notoriously hard to diagnose in the high myope as the visual field and the appearance of the optic disc are often abnormal due to the myopia. To diagnose glaucoma you would need also optic nerve OCT, you would need to know your corneal thickness.  Thin cornea bad, thick cornea good, normal corneal thickness neutral. You would need several visual fields as optic neuritis can also cause field defects.
3. If you have glaucoma timolol is NOT a good choice because it has so many side effects especially in young people: reduced exercise and work tolerance, fatigue, low blood pressure, slow pulse, depression, chronic cough, difficulty and breathing, wheezing, cold feet. A much better choice would be latanoprost once daily at bedtime.
4. You may have had a viral (usually adenovirus) conjunctival and corneal infection. It can cause pain, blurred vision that can last for months and irregular corneal astigmatism.
5. No way I can tell if you had optic neuritis(ON) or not. ON would not cause astigmatism or increase of IOP. It might cause pain, blurred vision and enlarged blind spot and light streaks and arc.
6. You might want to step back and get the tests mentioned above if you have not had them.
7. You might want to see a neuro-ophthalmologist if you have access to one for an independent opinion about the unusual constellation of symptoms you have.